"The Linux operating system for the Raspberry Pi bare-bones computer is ready to download. The Arch Linux ARM download is based on Arch Linux, which the Raspberry Pi Foundation says 'provides a lightweight base structure that allows you to shape the system to your needs'."

Canonical have publicly stated that they're trying to make inroads on tablets and other such embedded devices and you can see their intention with Unity and how it scales better for embedded devices (from TVs through to tablets) than a traditional WIMP environment would.